Not applicable.
The present invention relates to flush valves that control the flow of water from toilet tanks to toilet bowls, and in particular, to flush valves providing improved protection against overflows from toilet bowls.
A variety of systems are known for controlling the flush of toilet tank water to a toilet bowl. See e.g. U.S. Pat. Nos. 3,072,919, 3,988,785, 4,365,365, 5,794,279 and 5,848,422. Most of these systems include an outlet near the bottom of the toilet tank with a trip-activated flapper valve positioned adjacent the outlet. There is also an inlet valve for the tank that is typically controlled by a float that senses tank water level.
Depressing a trip lever raises the flapper, thereby unsealing the outlet so that water can empty from the tank into the bowl. As the tank water drains, the inlet valve float drops with the water level in the tank, thereby triggering inlet water flow. However, normally the water level drops faster than the inlet water enters. The flapper then can drop down to reseal the outlet, and the water level in the tank can be re-established. As the tank refills, the inlet valve float rises with the water and eventually closes the inlet valve to shut off the incoming water.
However, if the bowl trap were to be become obstructed, water from the tank would flood into the bowl through the rim openings and fill the bowl. The obstruction would prevent the bowl from emptying, and the water in the bowl would rise to the rim level.
If the outlet opening were positioned sufficiently high above the rim level, this would not interfere with the tendency of the flapper to reseal. However, if the outlet opening were positioned at or below the rim level, as might be desired in the design of an extremely low profile toilet to preserve tank water capacity, this might prevent the flapper from resealing. This could lead to an overflow condition (as in the absence of the flapper closing the outlet, the inlet water valve will not shut off).
Thus, a need exists for improved overflow protection in connection with flapper valves used for low profile toilets.
In one form, the invention provides a flapper valve assembly for regulating the passage of water out from a toilet water tank. The tank is of the type having a lower outlet opening. There is a flapper seal for seating against a seal surface of the outlet opening, and an attachment site for attaching a trip connector adjacent the flapper seal. There is also a yoke supporting the flapper seal adjacent an outer end of the yoke, and having a pivot axis adjacent an inward end of the yoke. A flapper arm has a first segment connected to the yoke adjacent the pivot axis, and a second segment extending at least partially in an outward direction.
In preferred forms the second segment of the flapper arm has a U-bend in it, or is otherwise provided with extra weight. When the flapper seal is horizontal, the second segment preferably extends at between 30 degrees and 60 degrees from vertical. The above assembly is particularly well suited for use when the flapper seal has an inner cavity and is supported by a yoke having a pair of legs (each having an opening defining the pivot axis).
In another aspect the invention provides a toilet tank. There is a tank housing with a lower outlet and a flapper seal pivotably positioned adjacent the outlet to control flow out the outlet. There is also a flapper arm coupled to the seal. The flapper arm is configured such that it delays seating of the flapper seal against the outlet when the water in the water tank is above a first specified level and assists seating of the flapper seal against the outlet when the water is either below that first specified level, or a second lower level.
The invention provides a flapper valve assembly that can be retrofit onto existing toilets to reduce the incidence of overflow. The flapper valve assembly can also be incorporated into newly designed toilets that have lower drain outlets.
As will be appreciated from the following, a primary aspect of the invention is the provision of a weighted element that is above the flapper when the flapper is horizontal or near horizontal. It can therefore help drive the flapper down even when there is some residual water in the tank (e.g. due to a bowl overflow condition). However, when the flapper is angled upward to a sufficient extent, the primary arm weight is shifted to an opposite side of a pivot axis. In this position, the arm retards flapper closure, thereby avoiding premature closure of the valve when the toilet tank hasn""t completely emptied (during normal operation).
Advantages of the present invention therefore include:
(a) reducing the risk of an overflow from toilets;
(b) permitting toilets to be designed with lower profiles while retaining adequate water capacity for proper cleaning cycles; and
(c) providing flapper assemblies of the above kind which can be retrofit into existing toilets. These and other advantages of the invention will be apparent from the detailed description and drawings.